This invention relates to wheel bearing assemblies for supporting a wheel and, more particularly, to an apparatus and method for attenuating impact forces transmitted to ball bearings in a wheel bearing assembly.
A wheel bearing assembly is used between a spindle and either a support member or a wheel hub (depending on the particular assembly configuration) for permitting relative rotation between the spindle and the support member or wheel hub. As larger diameter wheels, lower profile tires, and more rigid vehicle suspension components are employed in newer vehicle platforms, the vehicle wheel bearing assembly has become much more susceptible to damage resulting from side impact forces between the vehicle wheels and objects such as curbs. These side impact forces act in a direction generally parallel to the axis of the spindle and are transmitted to the bearing rolling elements (such as balls or rollers) and thence to the bearing raceways in which the rolling elements travel. Where the transferred forces create stresses that exceed the elastic limit of the raceway material, the rolling elements may produce permanent surface indentations in the raceways (a phenomenon known as “Brinelling”.) This can lead to undesirable noise and vibration in the bearing during use. To help prevent Brinelling, previous designs have focused on increasing the diameter or relative size of the rolling elements of the bearing. However, this approach increases the mass, weight and cost of the bearing components and can render the bearing design inefficient in terms of vehicle straight-running and cornering capabilities.
For the reasons outlined above, it is desirable to dampen or otherwise reduce the impact forces transmitted to the bearing rolling elements.